Fibroadenomas (fy-broe-ad-uh-NO-muhz) are solid, noncancerous breast tumors that occur most often in adolescent girls and women under the age of 30.

You might describe a fibroadenoma as firm, smooth, rubbery or hard with a well-defined shape. Usually painless, a fibroadenoma might feel like a marble in your breast, moving easily under your skin when touched. Fibroadenomas vary in size, and they can get bigger or even shrink on their own.

Fibroadenomas are among the most common breast lumps in young women. Treatment may include monitoring to detect changes in the size or feel of the fibroadenoma, a biopsy to evaluate the lump, or surgery to remove it.

Fibroadenomas are solid breast lumps or masses that usually are:

Round with distinct borders

Easily moved

Firm or rubbery

Painless

A fibroadenoma may feel like a marble within your breast when you press on it. You can have one or many fibroadenomas. Fibroadenomas range in size from being too small to be felt — detected only by mammogram or ultrasound — to 3 inches (8 centimeters) or more in diameter.

When to see a doctor

In healthy women, normal breast tissue often feels lumpy. If you detect a new breast lump or a change in your breasts — or if a breast lump you've had checked before seems to have grown or otherwise changed — make an appointment with your doctor.

Doctors don't know what causes fibroadenomas, but development of fibroadenomas may be related to reproductive hormones. Fibroadenomas occur more often during your reproductive years, can become bigger during pregnancy or use of hormone therapy, and may even shrink after menopause, when hormone levels decrease.

Most fibroadenomas don't affect your risk of breast cancer. However, your breast cancer risk might increase slightly if you have a complex fibroadenoma — which may contain abnormal cysts or dense, opaque tissue called calcifications. A pathologist makes the diagnosis of a complex fibroadenoma after reviewing the tissue from a biopsy of the lump.

You're likely to start by seeing your family doctor or gynecologist. It's a good idea to prepare for your appointment. Here's some information to help you.

What you can do

Be aware of pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.

Write down symptoms you're experiencing, including any that may seem unrelated to your breast changes.

Write down key personal information, such as past illnesses or current medical conditions.

Make a list of all medications, vitamins or supplements you're taking.

Bring a family member or friend along, if possible. Someone who accompanies you may remember something that you missed or forgot.

Write down questions to ask your doctor, listing them in order of importance in case time runs out.

For a fibroadenoma, basic questions to ask your doctor include:

What do you think this lump might be?

What kind of tests might I need? Do I need to do anything special to prepare for them?

What treatments are available?

Do you have brochures or other written materials about this topic? What websites do you recommend?

Don't hesitate to ask other questions as they occur to you during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

When did you notice the lump? Has it gotten bigger since then?

Does the lump change in size around the time of your menstrual periods?

Have you or other family members had breast problems?

What date did your last menstrual period begin?

Is the lump tender or painful?

Have you had nipple discharge?

Has anyone in your family had breast cancer?

Have you ever had a mammogram? If so, when?

During the physical exam, your doctor will check both breasts for lumps and other problems. Depending on your age and the characteristics of the lump, your doctor may recommend one or more of the following tests:

Diagnostic mammography. Mammography uses X-rays to produce an image (mammogram) of suspicious areas in your breast tissue. A fibroadenoma usually appears on a mammogram as a breast mass with smooth, round edges, distinct from surrounding breast tissue.

If you're younger than 30 and have a lump that can be felt, you'll likely start with an ultrasound to evaluate the lump and then have a diagnostic mammogram if needed to further assess the lump. If you're older than 30, you'll likely have a diagnostic mammogram of both breasts followed by an ultrasound to assess the lump.

Breast ultrasound can help your doctor determine whether a breast lump is solid or filled with fluid. A solid mass is more likely a fibroadenoma, and a fluid-filled mass is more likely a cyst.

Fine-needle aspiration. Through a thin needle inserted into your breast, your doctor attempts to withdraw the contents of the breast lump. If fluid comes out, the lump is most likely a cyst.

Core needle biopsy. Based on your physical exam and breast imaging findings, your doctor may recommend a core needle biopsy. This test uses a larger needle than the one used in fine-needle aspiration to collect tissue samples from the lump, which go to a lab for analysis.

In many cases, fibroadenomas require no treatment. However, some women choose to have their fibroadenomas surgically removed for their peace of mind.

Nonsurgical management

If your doctor is reasonably certain that your breast lump is a fibroadenoma — based on the results of the clinical breast exam, imaging test and biopsy — you may not need surgery.

You might decide to avoid surgery because:

Surgery can distort the shape and texture of the breast

Fibroadenomas sometimes shrink or disappear on their own

The breast has multiple fibroadenomas that appear to be stable — no changes in size on an ultrasound compared to an earlier ultrasound

If you choose not to have surgery, it's important to monitor the fibroadenoma with follow-up visits to your doctor for breast ultrasounds to detect any changes in the appearance or size of the lump. If you later become worried about the fibroadenoma, you can reconsider surgery to remove it.

Surgery

Your doctor might recommend surgery to remove the fibroadenoma if one of your tests — the clinical breast exam, an imaging test or a biopsy — is abnormal.

Procedures to remove a fibroadenoma include:

Lumpectomy or excisional biopsy. In this procedure, a surgeon removes breast tissue and sends it to a lab to check for cancer.

Cryoablation. In this alternative to excisional biopsy, your doctor inserts a thin, wand-like device (cryoprobe) through your skin to the fibroadenoma. A gas is used to freeze the tissue. Some fibroadenomas are too large to freeze, and cryoablation is only used if the diagnosis is certain.

After a fibroadenoma is removed, it's possible that one or more new fibroadenomas may develop. New breast lumps need to be assessed with mammograms, ultrasound and possibly biopsy — to determine if the lump is a fibroadenoma or cancer.

Reprint Permissions

A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.